A spokesperson has confirmed the musician-and-producer - who has dated a host of women, including model Daisy Lowe and actress Rashida Jones, before meeting Josephine in late 2009 - plans to wed the French model-and-actress, after pictures of her posing with an engagement ring were published in Purple magazine.
Just recently 35-year-old Mark - the brother of DJ Samantha Ronson - revealed he wanted to tie the knot with Josephine because he wanted to "share" everything with her.
He said: "It`s not the thought of the wedding - though that`s nice. It`s just the idea of marrying someone you really, really love that you just want to share that with."
Mark - who divides his time between London and New York - has also previously claimed he is a "romantic" lover, but Josephine`s nationality meant he had to up his game.
He said: "I think I`m fairly romantic. But then having a French girlfriend automatically sets the bar to a whole new level.
"I`m certainly not perfect. Nobody is. In every great relationship you have two people that really care about each other and, inevitably, they can wind each other up in ways that no one else is capable of."